Compound and thin film transistor and electronic device

ABSTRACT

Disclosed are a compound represented by Chemical Formula 1A or 1B, an organic thin film including the same, a thin film transistor, and an electronic device.In Chemical Formulae 1A and 1B, X1, X2, R1 to R4, and n1 are the same as described in the detailed description.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.16/546,842, filed Aug. 21, 2019, which claims priority to and thebenefit of Korean Patent Application No. 10-2018-0101500 filed in theKorean Intellectual Property Office on Aug. 28, 2018, the entirecontents of each of which are incorporated herein by reference.

BACKGROUND 1. Field

A compound, a thin film transistor, and an electronic device aredisclosed.

2. Description of Related Art

A flat panel display such as a liquid crystal display (LCD) or anorganic light emitting diode (OLED) display includes a thin filmtransistor (TFT) that is a three-terminal element as a switch.Researches on an organic thin film transistor (OTFT) including anorganic semiconductor such as a small molecular semiconductor or polymersemiconductor instead of an inorganic semiconductor such as a silicon(Si) semiconductor as one kind of the thin film transistor are beingactively conducted.

The organic thin film transistor may be made as a fiber or a film due tocharacteristics of an organic material, and thus is drawing attention asa core element for a flexible display device. The organic thin filmtransistor may be manufactured using a solution process such as inkjetprinting, and may be easily applied to a large area flat panel displaywhere a deposition process has a limit.

SUMMARY

An embodiment provides a compound applicable to an electronic devicesuch as a thin film transistor.

Another embodiment provides an organic thin film including the compound.

Yet another embodiment provides a thin film transistor including thecompound.

Still another embodiment provides an electronic device including thethin film transistor.

According to one embodiment, a compound represented by Chemical Formula1A or 1B is provided.

In Chemical Formulae 1A and 1B,

X¹ and X² are different from each other and are independently one of O,S, Se, and Te,

R¹ to R⁴ are independently one of hydrogen, a substituted orunsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynylgroup, a substituted or unsubstituted C1 to C30 alkoxy group, asubstituted or unsubstituted C6 to C30 aryl group, a substituted orunsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C3to C30 heteroaryl group, a halogen, a cyano group, or a combinationthereof, and

n₁ is an integer ranging from 1 to 4.

In some embodiments, one of X¹ and X² may be Se or Te.

In some embodiments, one of X¹ and X2 may be S.

In some embodiments, R¹ and R² may be different from each other.

In some embodiments, one of R¹ and R² may be hydrogen and the other ofR¹ and R² may be one of a substituted or unsubstituted C1 to C30 alkylgroup, a substituted or unsubstituted C2 to C30 alkenyl group, asubstituted or unsubstituted C2 to C30 alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6to C30 aryl group, a substituted or unsubstituted C6 to C30 aryloxygroup, a substituted or unsubstituted C3 to C30 heteroaryl group, ahalogen, a cyano group, or a combination thereof.

In some embodiments, one of R¹ and R² may be one of a substituted orunsubstituted C1 to C30 linear alkyl group, a substituted orunsubstituted C2 to C30 linear alkenyl group, a substituted orunsubstituted C2 to C30 linear alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, or a combination thereof and theother of R¹ and R² may be one of a substituted or unsubstituted C1 toC30 branched alkyl group, a substituted or unsubstituted C2 to C30branched alkenyl group, a substituted or unsubstituted C2 to C30branched alkynyl group, or a combination thereof.

In some embodiments, one of R¹ and R² may be one of a substituted orunsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynylgroup, a substituted or unsubstituted C1 to C30 alkoxy group, or acombination thereof and the other of R¹ and R² may be one of asubstituted or unsubstituted C6 to C30 aryl group, a substituted orunsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C3to C30 heteroaryl group, or a combination thereof.

In some embodiments, one of R¹ and R² may include a group represented byone of Chemical Formulae 2A to 2C.

In Chemical Formulae 2A to 2C,

Z¹ to Z³ may independently be N or CR^(a),

one of Z¹ to Z³ may be N,

X³ may be one of O, S, Se, Te, NR^(b), or CR^(c)R^(d),

m1 may be an integer ranging from 0 to 5,

m2 may be an integer ranging from 0 to 3,

R⁵, R⁶, and R^(a) to R^(d) may independently be one of hydrogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof,

when m1 is two or more, each R⁵ may be the same or different and twoadjacent R⁵'s may be independently present or linked with each other toform a ring, and

when m2 is two or more, each R⁶ may be the same or different and twoadjacent R⁶'s may be independently present or linked with each other toform a ring.

In some embodiments, X¹ may be O or S, X² may be Se or Te, one of R¹ andR² may be hydrogen, and the other of R1 and R2 may be one of asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof.

In some embodiments, X¹ may be O or S, X² may be Se or Te, one of R¹ andR² may be one of a substituted or unsubstituted C1 to C30 linear alkylgroup, a substituted or unsubstituted C2 to C30 linear alkenyl group, asubstituted or unsubstituted C2 to C30 linear alkynyl group, asubstituted or unsubstituted C1 to C30 alkoxy group, or a combinationthereof and the other of R¹ and R² may be one of a substituted orunsubstituted C1 to C30 branched alkyl group, a substituted orunsubstituted C2 to C30 branched alkenyl group, a substituted orunsubstituted C2 to C30 branched alkynyl group, or a combinationthereof.

In some embodiments, X¹ may be O or S, X² may be Se or Te, one of R¹ andR² may be one of a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, or a combination thereof and the other of R¹ and R²may be one of a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, or a combination thereof.

In some embodiments, X¹ may be one of S, Se, and Te. X² may be one of O,S, Se, and Te.

In some embodiments, one of R¹ and R² may be one of a substituted orunsubstituted C1 to C30 linear alkyl group, a substituted orunsubstituted C2 to C30 linear alkenyl group, a substituted orunsubstituted C2 to C30 linear alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, or a combination thereof. Theother of R¹ and R² may be one of a substituted or unsubstituted C4 toC30 branched alkyl group, a substituted or unsubstituted C4 to C30branched alkenyl group, a substituted or unsubstituted C4 to C30branched alkynyl group, or a combination thereof.

In some embodiments, the compound may include a group listed in Group 1:

In some embodiments, the compound may include a group listed in Group 2:

In Group 2,

R^(1a) may be hydrogen or a substituted or unsubstituted C1 to C30 alkylgroup,

Z¹ to Z³ may independently be N or CR^(a),

one of Z¹ to Z³ may be N,

X³ may be one of O, S, Se, Te, NR^(b), or CR^(c)R^(d),

p and q independently may be an integer of 1 to 30, and

R^(p) and R^(a) to R_(d) may independently be one of hydrogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof.

According to another embodiment, an organic thin film including thecompound is provided.

According to another embodiment, a thin film transistor may include agate electrode, an organic semiconductor (also referred to as an organicsemiconductor layer) overlapping with the gate electrode, and a sourceelectrode and a drain electrode electrically connected to the organicsemiconductor. The organic semiconductor may include a compoundrepresented by Chemical Formula 1A or 1B.

According to yet another embodiment, an electronic device may includethe organic thin film.

According to still another embodiment, an electronic device may includethe thin film transistor.

The compound may effectively be applied to a deposition or solutionprocess and simultaneously improve charge mobility and current on-offratio.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a thin film transistoraccording to an embodiment,

FIG. 2 is a graph showing XRD of the organic thin film according toPreparation Example 1,

FIG. 3 is a graph showing XRD of the organic thin film according toComparative Preparation Example 1,

FIG. 4 is a graph showing XRD of the organic thin film according toPreparation Example 2, and

FIG. 5 is a graph showing XRD of the organic thin film according toComparative Preparation Example 2.

DETAILED DESCRIPTION

Example embodiments will hereinafter be described in detail, and may beeasily performed by a person having an ordinary skill in the relatedart. However, this disclosure may be embodied in many different formsand is not to be construed as limited to the example embodiments setforth herein.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itmay be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.

As used herein, when a definition is not otherwise provided,“substituted” may refer to replacement of hydrogen of a compound or agroup by a substituent selected from a halogen atom, a hydroxy group, anitro group, a cyano group, an amino group, an azido group, an amidinogroup, a hydrazino group, a hydrazono group, a carbonyl group, acarbamyl group, a thiol group, an ester group, a carboxyl group or asalt thereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C1 to C20 alkyl group, a C2 to C20 alkenylgroup, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C3 to C30heteroaryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxy group,a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl group, a C3to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 to C15cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and acombination thereof.

As used herein, when a definition is not otherwise provided, “hetero”may refer to inclusion of one to four heteroatoms selected from N, O, S,Se, Te, Si, and P.

As used herein, when a definition is not otherwise provided, “alkylgroup” may refer to a linear or branched, saturated, monovalenthydrocarbon group (e.g., a methyl group, an ethyl group, a propyl group,an isobutyl group, a sec-butyl group, a tert-butyl group, a pentylgroup, an iso-amyl group, a hexyl group, etc.).

As used herein, when a definition is not otherwise provided, “alkenylgroup” may refer to a linear or branched, saturated, monovalenthydrocarbon group (e.g., ethenyl group) having at least onecarbon-carbon double bond.

As used herein, when a definition is not otherwise provided, “alkynylgroup” may refer to a linear or branched saturated monovalenthydrocarbon group including at least one carbon-carbon triple bond(e.g., ethynyl group).

As used herein, when a definition is not otherwise provided, “alkoxygroup” may refer to an alkyl group that is linked via oxygen, forexample a methoxy, an ethoxy, and a sec-butyloxy group.

As used herein, when a definition is not otherwise provided, “arylgroup” may refer to a monovalent functional group formed by the removalof one hydrogen atom from one or more rings of an arene, e.g., phenyl,biphenyl, or naphthyl. The arene may refer to a hydrocarbon having anaromatic ring, and includes monocyclic and polycyclic hydrocarbons,wherein the additional ring(s) of the polycyclic hydrocarbon may bearomatic or nonaromatic.

As used herein, when a definition is not otherwise provided, “heteroarylgroup” may refer to an aryl group or a cyclic group including at leastone heteroatom selected from N, O, S, Se, Te, P, and Si instead ofcarbon (C) in the aryl group or the cyclic group. When the heteroarylgroup is a fused ring, at least one of rings of the heteroaryl group mayhave a heteroatom or each ring may have a heteroatom.

As used herein, when a definition is not otherwise provided, “alkylarylgroup” may refer to an aryl group where at least one hydrogen atom isreplaced by an alkyl group.

As used herein, when a definition is not otherwise provided, “arylalkylgroup” may refer to an alkyl group where at least one hydrogen atom isreplaced by an aryl group.

As used herein, when a definition is not otherwise provided, “aryloxygroup” may refer to an aryl group that is linked via oxygen, and thearyl group is the same as described above.

As used herein, when a definition is not otherwise provided, “arylalkylgroup” may refer to an aryl group where at least one hydrogen atom isreplaced by a lower alkylene, e.g., methylene, ethylene, propylene, andthe like. For example, the “arylalkyl group” may be a benzyl group or aphenylethyl group.

As used herein, when a definition is not otherwise provided, “cycloalkylgroup” may refer to a monovalent functional group having one or moresaturated rings in which all ring members are carbon, e.g., acyclopentyl group and a cyclohexyl group.

As used herein, when a definition is not otherwise provided,“heteroalkyl group” may refer to the alkyl group defined above wheremethylene (—(CH)2-) is replaced by —O—, —S—, —S(═O)2-, —Se—, or —NR—(wherein R is hydrogen or a C1 to C10 alkyl group).

As used herein, when a definition is not otherwise provided,“arylheteroalkyl group” may refer to the heteroalkyl group defined abovewhere at least one hydrogen atom is replaced by an aryl group.

As used herein, when a definition is not otherwise provided,“heteroarylalkyl group” may refer to the alkyl group defined above whereat least one hydrogen atom is replaced by a heteroaryl group.

As used herein, when a definition is not otherwise provided,“alkylheteroaryl group” may refer to the heteroaryl group defined abovewhere at least one hydrogen atom is replaced by an alkyl group.

As used herein, when a definition is not otherwise provided, “aromaticring” may refer to a functional group in which all atoms in the cyclicfunctional group have a p-orbital, and wherein these p-orbitals areconjugated. For example, the aromatic ring may be a C6 to C20 arylgroup.

Expressions such as “at least one of,” when preceding a list of elements(e.g., A, B, and C), modify the entire list of elements and do notmodify the individual elements of the list. For example, “at least oneof A, B, and C,” “at least one of A, B, or C,” “one of A, B, C, or acombination thereof,” and “one of A, B, C, and a combination thereof,”respectively, may be construed as covering any one of the followingcombinations: A; B; C; A and B; A and C; B and C; and A, B, and C.”

Hereinafter, a compound according to an embodiment is described.

A compound according to an embodiment may be represented by ChemicalFormula 1A or 1B.

In Chemical Formulae 1A and 1B,

X¹ and X² are different from each other and are independently one of O,S, Se, and Te,

R¹ to R⁴ are independently one of hydrogen, a substituted orunsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynylgroup, a substituted or unsubstituted C1 to C30 alkoxy group, asubstituted or unsubstituted C6 to C30 aryl group, a substituted orunsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C3to C30 heteroaryl group, a halogen, a cyano group, or a combinationthereof, and

n₁ is an integer ranging from 1 to 4.

The compound is a fused polycyclic aromatic compound including a fusedpolycyclic aromatic ring where three to six rings are fused as a corestructure. The core structure has a structure where an aryl grouplocated between the pentagonal heterocyclic rings at both terminal endsis fused. The pentagonal heterocyclic rings at both terminal ends havedifferent heteroatoms to form an asymmetric core structure.

Such a fused polycyclic aromatic compound having an asymmetric corestructure may have a high crystallinity and thus may improve chargemobility. In addition, the fused polycyclic aromatic compound having anasymmetric core structure may exhibit liquid crystallinity at a desired(and/or alternatively predetermined) temperature region, therebyincreasing alignment of molecules. Herein, the temperature regionexhibiting liquid crystallinity may be relatively low, thereby loweringa process temperature. Accordingly, the fused polycyclic aromaticcompound having an asymmetric core structure may have high chargemobility due to its high crystallinity and molecular arrangement, andsimultaneously, the process temperature may be lowered to limit and/orprevent deterioration of the compound and damage caused by cracks of thethin film.

For example, X¹ and X2 may be different from each other and mayindependently be one of S, Se, and Te.

For example, X¹ and X² may be different and one of X¹ and X² may be S.

For example, X¹ and X² may be different and one of X¹ and X² may be Seor Te.

For example, one of X¹ and X2 may be S, and the other of X¹ and X² maybe Se or Te.

For example, one of X¹ and X² may be Se, and the other of X¹ and X² maybe Te.

For example, n1 may be an integer in a range of 1 to 4 and/or 1 to 3,and thus the compound may be a fused polycyclic aromatic compoundincluding a fused polycyclic aromatic ring where three to six rings orthree to five rings are fused, as a core structure.

For example, the compound may be an unsubstituted fused polycyclicaromatic compound.

For example, the compound may be a fused polycyclic aromatic compoundhaving at least one substituent, and namely at least one of R¹ to R⁴ maynot be hydrogen.

For example, the compound may be a fused polycyclic aromatic compoundhaving an asymmetric substituted structure, and namely R¹ and R² may bedifferent and/or R³ and R⁴ may be different.

For example, the compound may have a substituent at one side of thefused polycyclic aromatic ring.

For example, one of R¹ and R² may be hydrogen and the other of R¹ and R²may be one of a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C6 to C30 aryloxy group, asubstituted or unsubstituted C3 to C30 heteroaryl group, a halogen, acyano group, or a combination thereof.

For example, one of R³ and R⁴ may be hydrogen and the other of R³ and R⁴may be one of a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C6 to C30 aryloxy group, asubstituted or unsubstituted C3 to C30 heteroaryl group, a halogen, acyano group, or a combination thereof.

For example, the compound may have a linear substituent at one side ofthe fused polycyclic aromatic ring and a non-linear substituent at theother side of the fused polycyclic aromatic ring.

For example, one of R¹ and R² may be one of a substituted orunsubstituted C1 to C30 linear alkyl group, a substituted orunsubstituted C2 to C30 linear alkenyl group, a substituted orunsubstituted C2 to C30 linear alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, or a combination thereof and theother of R1 and R² may be a substituted or unsubstituted C1 to C30branched alkyl group, a substituted or unsubstituted C2 to C30 branchedalkenyl group, a substituted or unsubstituted C2 to C30 branched alkynylgroup, or a combination thereof.

For example, one of R³ and R⁴ may be one of a substituted orunsubstituted C1 to C30 linear alkyl group, a substituted orunsubstituted C2 to C30 linear alkenyl group, a substituted orunsubstituted C2 to C30 linear alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, or a combination thereof and theother of R3 and R4 may be a substituted or unsubstituted C1 to C30branched alkyl group, a substituted or unsubstituted C2 to C30 branchedalkenyl group, a substituted or unsubstituted C2 to C30 branched alkynylgroup, or a combination thereof.

For example, the compound may have a non-cyclic substituent at one sideof the fused polycyclic aromatic ring and a cyclic substituent at theother side of the fused polycyclic aromatic ring.

For example, one of R¹ and R² may be one of a substituted orunsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynylgroup, a substituted or unsubstituted C1 to C30 alkoxy group, or acombination thereof and the other of R¹ and R² may be a substituted orunsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 toC30 aryloxy group, a substituted or unsubstituted C3 to C30 heteroarylgroup, or a combination thereof.

For example, one of R³ and R⁴ may be one of a substituted orunsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynylgroup, a substituted or unsubstituted C1 to C30 alkoxy group, or acombination thereof and the other of R³ and R⁴ may be a substituted orunsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 toC30 aryloxy group, a substituted or unsubstituted C3 to C30 heteroarylgroup, or a combination thereof.

For example, the compound may have a cyclic substituent at one side ofthe fused polycyclic aromatic ring and a heterocyclic substituent at theother side of the fused polycyclic aromatic ring.

For example, one of R¹ and R² may be one of a substituted orunsubstituted C6 to C30 aryl group or a substituted or unsubstituted C6to C30 aryloxy group and the other of R¹ and R² may be a substituted orunsubstituted C3 to C30 heteroaryl group.

For example, one of R³ and R⁴ may be one of a substituted orunsubstituted C6 to C30 aryl group or a substituted or unsubstituted C6to C30 aryloxy group and the other of R³ and R⁴ may be a substituted orunsubstituted C3 to C30 heteroaryl group.

For example, one of R¹ and R² may include one of a substituted orunsubstituted C6 to C30 aryl group or a substituted or unsubstituted C3to C30 heteroaryl group, and for example one of R¹ and R² may include agroup represented by one of Chemical Formulae 2A to 2C.

In Chemical Formulae 2A to 2C,

Z¹ to Z³ are each N or CR^(a),

one of Z¹ to Z³ is N,

X³ is one of O, S, Se, Te, NR^(b), or CR^(c)R^(d),

m1 is an integer ranging from 0 to 5,

m2 is an integer ranging from 0 to 3,

R⁵, R⁶, and R^(a) to R^(d) are independently one of hydrogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof,

when m1 is two or more, each R⁵ is the same or different and twoadjacent R⁵'s are independently present or linked with each other toform a ring, and

when m2 is two or more, each R⁶ is the same or different and twoadjacent R⁶'s are independently present or linked with each other toform a ring.

For example, at least one of R³ and R⁴ may include one of a substitutedor unsubstituted C6 to C30 aryl group or a substituted or unsubstitutedC3 to C30 heteroaryl group, and for example one of R3 and R4 may includea group represented by one of Chemical Formulae 2A to 2C.

For example, R³ and R⁴ may independently be hydrogen.

For example, in Chemical Formula 1A or 1B, X¹ may be O or S, X² may beSe or Te, one of R¹ and R² may be hydrogen, and the other of R¹ and R²may be one of a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C6 to C30 aryloxy group, asubstituted or unsubstituted C3 to C30 heteroaryl group, a halogen, acyano group, or a combination thereof.

For example, in Chemical Formula 1A or 1B, X¹ may be O or S, X² may beSe or Te, one of R¹ and R² may be one of a substituted or unsubstitutedC1 to C30 linear alkyl group, a substituted or unsubstituted C2 to C30linear alkenyl group, a substituted or unsubstituted C2 to C30 linearalkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, ora combination thereof, and the other of R¹ and R² may be one of asubstituted or unsubstituted C1 to C30 branched alkyl group, asubstituted or unsubstituted C2 to C30 branched alkenyl group, asubstituted or unsubstituted C2 to C30 branched alkynyl group, or acombination thereof.

For example, in Chemical Formula 1A or 1B, X¹ may be O or S, X2 may beSe or Te, one of R1 and R2 may be one of a substituted or unsubstitutedC1 to C30 linear alkyl group, a substituted or unsubstituted C2 to C30linear alkenyl group, a substituted or unsubstituted C2 to C30 linearalkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, ora combination thereof, and the other of R¹ and R² may be one of asubstituted or unsubstituted C1 to C30 branched alkyl group, asubstituted or unsubstituted C2 to C30 branched alkenyl group, asubstituted or unsubstituted C2 to C30 branched alkynyl group, or acombination thereof.

For example, in Chemical Formula 1A or 1B, X1 may be O or S, X2 may beSe or Te, one of R1 and R2 may be one of a substituted or unsubstitutedC1 to C30 alkyl group, a substituted or unsubstituted C2 to C30 alkenylgroup, a substituted or unsubstituted C2 to C30 alkynyl group, asubstituted or unsubstituted C1 to C30 alkoxy group, or a combinationthereof, and the other of R1 and R2 may be one of a substituted orunsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 toC30 aryloxy group, a substituted or unsubstituted C3 to C30 heteroarylgroup, or a combination thereof.

The compound may be for example one of the compounds of Group 1, but isnot limited thereto.

In Group 1, R¹ and R² are the same as described above.

The compound may be for example one of the compounds of Group 2, but isnot limited thereto.

In Group 2,

R^(1a) may be hydrogen or a substituted or unsubstituted C1 to C30 alkylgroup,

Z¹ to Z³ may independently be N or CR^(a), one of Z¹ to Z³ may be N,

X³ may be one of O, S, Se, Te, NR^(b), or CR^(c)R^(d),

p and q may independently be an integer of 1 to 30, and

R^(p) and R^(a) to R^(d) are independently one of hydrogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof.

An organic thin film may be formed from the compound. The organic thinfilm may be formed by a deposition to be a deposited film or the organicthin film may be formed by coating to a coating thin film.

The organic thin film may be applied to various devices including anorganic semiconductor. For example, the compound may be applied to athin film transistor and may be applied to a charge transport layerand/or an active layer of an electronic device such as a solar cell, anorganic light emitting diode (OLED) display, and an organic sensor.

Hereinafter, one example of a thin film transistor including thecompound is described referring to the drawing.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

FIG. 1 is a cross-sectional view showing a thin film transistoraccording to an embodiment.

A gate electrode 124 is formed on a substrate 110 made of transparentglass, a semiconductor (e.g., silicon), or plastic. The gate electrode124 is connected to a gate line (not shown) for transferring a gatesignal. The gate electrode 124 may be made of gold (Au), copper (Cu),nickel (Ni), aluminum (Al), molybdenum (Mo), chromium (Cr), tantalum(Ta), titanium (Ti), an alloy thereof, or a combination thereof. Thegate electrode 124 may be formed in the substrate 110 when the substrate110 is a silicon wafer.

A gate insulating layer 140 is formed on the gate electrode 124. Thegate insulating layer 140 may be made of an organic material and/or aninorganic material. Examples of the organic material may include asoluble polymer compound such as a polyvinyl alcohol-based compound, apolyimide-based compound, a polyacryl-based compound, apolystyrene-based compound, and benzocyclobutane (BCB), and examples ofthe inorganic material may include a silicon nitride (SiNx) and asilicon oxide (SiO²).

An organic semiconductor 154 is formed on the gate insulating layer 140.The organic semiconductor 154 may include the compound. The organicsemiconductor 154 may be formed in a solution process such as spincoating, slit coating, or inkjet printing by preparing the compound in aform of a solution. However, the organic semiconductor 154 may be formedby vacuum-depositing or thermal evaporating the compound. A sourceelectrode 173 and a drain electrode 175 are formed on the organicsemiconductor 154. The source electrode 173 and the drain electrode 175face each other on the organic semiconductor 154. The source electrode173 is electrically connected to the data line (not shown) transferringthe data signal. The source electrode 173 and the drain electrode 175may include at least one metal of gold (Au), copper (Cu), nickel (Ni),aluminum (Al), molybdenum (Mo), chromium (Cr), tantalum (Ta), titanium(Ti), an alloy thereof, or a combination thereof.

Although the bottom gate structured organic thin film transistor isprovided as an example of the organic thin film transistor, the organicthin film transistor is not limited thereto, and all organic thin filmtransistors including a top gate structured organic thin film transistormay be applied. Although the source electrode 173 and the drainelectrode 175 are positioned on the organic semiconductor 154 in FIG. 1, the organic thin film transistor is not limited thereto, and theorganic semiconductor 154 may be positioned on the source electrode 173and the drain electrode 175.

The thin film transistor may be applied to a switch or driving device ofvarious electronic devices, and the electronic device may include, forexample, a liquid crystal display (LCD), an organic light emitting diode(OLED) display, an electrophoretic display, an organic photoelectricdevice, and an organic sensor, but is not limited thereto.

Hereinafter, the embodiments are illustrated in more detail withreference to examples. However, these examples are non-limiting, andinventive concepts are not thereto.

Synthesis of Compound Synthesis Example 1

Synthesis of Compound 1b

Compound 1a (1 g, 2.38 mmol) (herein, C₁₀H₂₁ group is a linear alkylgroup) is dissolved in 50 mL of dry methyl dichloride (MC), and theresultant solution is cooled down to 0° C. Subsequently, triethylamine(Et₃N, 0.9 mL, 6.43 mmol) is added thereto, and the obtained mixture isstirred for 1 hour at 0° C. Then, trifluoromethanesulfonic anhydride(Tf₂O, 0.6 mL, 3.58 mmol) is slowly added thereto in a dropwise fashion,and the obtained mixture is slowly heated up to room temperature andstirred for 12 hours. Subsequently, 30 mL of an ammoniumchloride-saturated aqueous solution is added thereto, and an extract isobtained therefrom by using methyl dichloride and then, several timeswashed with water. Subsequently, the extract is dried with magnesiumsulfate, filtered, and after removing a solvent therefrom, purifiedthrough silica column chromatography to obtain Compound 1b. A yield is96%.

1H NMR (300 MHz, CDCl3): δ ppm 8.19 (s, 2H), 8.12 (s, 1H), 7.89 (s, 1H),7.09 (s, 1H), 2.94 (t, 2H), 1.79 (m, 2H), 1.36 (m, 14H), 0.87 (t, 3H)

Synthesis of Compound 1c

Compound 1b (1.26 g, 2.28 mmol), bis(triphenylphosphine) palladium (II)dichloride (Pd(PPh₃)₂Cl₂, 0.08 g, 0.11 mmol), and CuI (0.04 g, 0.23mmol) are dissolved in dimethyl formamide (30 mL) and triethylamine (6mL), and the resultant solution is cooled down to −78° C. Subsequently,ethynylbenzene (0.38 mL, 3.42 mmol) is added thereto, and the obtainedmixture is stirred for 5 hours, while slowly heated up to roomtemperature. Then, 30 mL of an ammonium chloride-saturated aqueoussolution is added thereto, and an extract is obtained therefrom by usingchloroform and then, several times washed with water. The extract isdried with magnesium sulfate, filtered, and after removing solventtherefrom, purified through silica column chromatography to obtainCompound 1c. A yield is 82%.

1H NMR (300 MHz, CDCl3): δ ppm 8.18 (s, 1H), 8.14 (d, 2H), 8.06 (s, 1H),7.63 (m, 2H), 7.39 (m, 3H), 7.07 (s, 1H), 2.92 (t, 2H), 1.78 (m, 2H),1.36 (m, 14H), 0.88 (t, 3H)

Synthesis of Compound 1d

Se (1.22 g, 15.5 mmol) is dissolved in 100 mL of ethanol, the resultantsolution is cooled down to 0° C., and NaBH₄ (0.59 g, 15.5 mmol) is addedthereto. The resulting material is dissolved in 15 mL ofN-methyl-2-pyrrolidone, and Compound 1c (5.2 g, 10.32 mmol) is addedthereto. After increasing the temperature up to 130° C., the obtainedmixture is stirred for 12 hours and cooled down to room temperature, anda solid produced therein is washed with methanol and chloroform toobtain Compound 1d as a yellow solid. A yield is 58%.

MS (MALDI-TOF-MS, m/z) 504.315

Comparative Synthesis Example 1

Synthesis of Compound 2b

Compound 2a (1 g, 2.38 mmol) is dissolved in 50 mL of dry methyldichloride, and the resultant solution is cooled down to 0° C.Subsequently, triethylamine (Et₃N, 0.9 mL, 6.43 mmol) is added thereto,and the obtained mixture is stirred for 1 hour at 0° C. Then,trifluoromethanesulfonic anhydride (Tf₂O, 0.6 mL, 3.58 mmol) is slowlyadded thereto in a dropwise fashion, and the obtained mixture is heatedup to room temperature and stirred for 12 hours. Subsequently, 30 mL ofan ammonium chloride-saturated aqueous solution is added thereto, and anextract is obtained therefrom by using methyl dichloride and then,several times washed with water. The extract is dried with magnesiumsulfate, filtered, and after removing a solvent therefrom, purifiedthrough silica column chromatography to obtain Compound 2b. A yield is96%.

1H NMR (300 MHz, CDCl3): δ ppm 8.19 (s, 2H), 8.12 (s, 1H), 7.89 (s, 1H),7.09 (s, 1H), 2.94 (t, 2H), 1.79 (m, 2H), 1.36 (m, 14H), 0.87 (t, 3H)

Synthesis of Compound 2c

Compound 2b (1.26 g, 2.28 mmol), bis(triphenylphosphine) palladium (II)dichloride (0.08 g, 0.11 mmol), and CuI (0.04 g, 0.23 mmol) aredissolved in 30 mL of dimethyl formamide and 6 mL of triethylamine, andthe resultant solution is cooled down to −78° C. Subsequently,ethynylbenzene (0.38 mL, 3.42 mmol) is added thereto, and the obtainedmixture is stirred for 5 hours, while heated up to room temperature.Then, 30 mL of an ammonium chloride-saturated aqueous solution is addedthereto, and an extract is obtained therefrom by using chloroform andthen, several times washed with water. The extract is dried by usingmagnesium sulfate, filtered, and after removing a solvent therefrom,purified through silica column chromatography to obtain Compound 2c. Ayield is 82%.

1H NMR (300 MHz, CDCl3): δ ppm 8.18 (s, 1H), 8.14 (d, 2H), 8.06 (s, 1H),7.63 (m, 2H), 7.39 (m, 3H), 7.07 (s, 1H), 2.92 (t, 2H), 1.78 (m, 2H),1.36 (m, 14H), 0.88 (t, 3H)

Synthesis of Compound 2d

Compound 2c (0.55 g, 1.09 mmol) is dissolved in 50 mL ofN-methyl-2-pyrrolidone, and Na₂S₉H₂O (0.63 g, 2.62 mmol) is addedthereto. After increasing the temperature up to 110° C., the obtainedmixture is stirred for 2 hours. Subsequently, after decreasing thetemperature down to room temperature, a yellow solid produced therefromis washed with chloroform and methanol and collected to obtain Compound2d. A yield is 80%.

MS (MALDI-TOF-MS, m/z) 456.343 (M+)

Synthesis Example 2

Synthesis of Compound 3b

Compound 3a (5 g, 12.2 mmol), bis(triphenylphosphine) palladium (II)dichloride (0.43 g, 0.6 mmol), and CuI (0.23 g, 1.2 mmol) are dissolvedin 125 mL of dimethyl formamide and 25 mL of triethylamine, and theresultant solution is cooled down to −78° C. Subsequently,ethynylbenzene (3.2 g, 13.2 mmol) is added thereto, and the obtainedmixture is stirred for 5 hours, while slowly heated up to roomtemperature. Then, 200 mL of distilled water is added thereto, and anextract is obtained therefrom with chloroform and then, several timeswashed with water. The extract is dried with magnesium sulfate,filtered, dried again, and a volume of chloroform is reduced, and afteradding hexane ten times as much as the chloroform thereto, a solidproduced therein is filtered to obtain Compound 3b as a white solid. Ayield is 65%.

1H NMR (300 MHz, CDCl3): δ ppm 8.25 (s, 2H), 8.20 (d, 2H), 7.56 (s, 1H),7.55 (d, 2H), 7.43 (d, 1H), 7.20 (d, 2H), 2.63 (t, 2H), 1.62 (m, 2H),1.30 (m, 14H), 0.88 (t, 3H)

Synthesis of Compound 3c

Se (1.2 g, 15.5 mmol) is dissolved in 100 mL of ethanol, the resultantsolution is cooled down to 0° C., and NaBH₄ (0.98 g, 25.8 mmol) is addedthereto. Subsequently, Compound 3b (4.7 g, 9.3 mmol) dissolved in 500 mLof N-methyl-2-pyrrolidone is added thereto. The obtained mixture isheated up to 130° C., stirred for 12 hours, and cooled down to roomtemperature, and a solid produced therein is washed with methanol andchloroform to obtain Compound 3c as a yellow solid. A yield is 66%.

MS (MALDI-TOF-MS, m/z) 504.220

Comparative Synthesis Example 2

Synthesis of Compound 4b

Compound 4a (5 g, 12.2 mmol), bis(triphenylphosphine) palladium (II)dichloride (0.43 g, 0.6 mmol), and CuI (0.23 g, 1.2 mmol) are dissolvedin 125 mL of dimethyl formamide and 25 mL of triethylamine, and thesolution is cooled down to −78° C. Subsequently, ethynylbenzene (3.2 g,13.2 mmol) is added thereto, and the obtained mixture is stirred for 5hours, while slowly heated up to room temperature. Then, 200 mL ofdistilled water is added thereto, and an extract is obtained therefromby using chloroform and then, several times washed with water. Theextract is dried with magnesium sulfate, filtered, dried again, and avolume of chloroform is reduced, and after adding hexane ten times asmuch as the chloroform, a solid produced therein is filtered to obtainCompound 4b as a white solid. A yield is 65%.

1H NMR (300 MHz, CDCl3): δ ppm 8.25 (s, 2H), 8.20 (d, 2H), 7.56 (s, 1H),7.55 (d, 2H), 7.43 (d, 1H), 7.20 (d, 2H), 2.63 (t, 2H), 1.62 (m, 2H),1.30 (m, 14H), 0.88 (t, 3H)

Synthesis of Compound 4c

Compound 4b (3.3 g, 6.55 mmol) is dissolved in N-methyl-2-pyrrolidone,and Na₂S₉H₂O (4.7 g, 19.66 mmol) is added thereto. Subsequently, theobtained mixture is heated up to 110° C. and then, stirred for 2 hours.After decreasing the temperature down to room temperature, a yellowsolid produced therein is washed with chloroform and methanol andcollected to obtain Compound 4c. A yield is 80%.

MS (MALDI-TOF-MS, m/z) 456.325 (M+)

Formation of Thin Film Preparation Example 1

The compound according to Synthesis Example 1 is vacuum vapor-depositedon a silicon wafer covered with 3000 Å thick SiO₂ at 70° C. to form a600 Å-thick organic thin film.

Preparation Example 2

An organic thin film is formed according to the same method asPreparation Example 1 except for using the compound according toSynthesis Example 2 instead of the compound according to SynthesisExample 1.

Comparative Preparation Example 1

An organic thin film is formed according to the same method asPreparation Example 1 except for using the compound according toComparative Synthesis Example 1 instead of the compound according toSynthesis Example 1.

Comparative Preparation Example 2

An organic thin film is formed according to the same method asPreparation Example 1 except for using the compound according toComparative Synthesis Example 2 instead of the compound according toSynthesis Example 1.

Evaluation I

Crystallinity of the organic thin films according to PreparationExamples 1 and 2 and Comparative Preparation Examples 1 and 2 isexamined.

The crystallinity is evaluated by comparing a full width at half maximum(FWHM) from an XRD spectrum peak measured with D8 Advance made by BrukerCompany.

FIG. 2 is a graph showing XRD of the organic thin film according toPreparation Example 1, FIG. 3 is a graph showing XRD of the organic thinfilm according to Comparative Preparation Example 1, FIG. 4 is a graphshowing XRD of the organic thin film according to Preparation Example 2,and FIG. 5 is a graph showing XRD of the organic thin film according toComparative Preparation Example 2.

Referring to FIGS. 2 and 3 , the organic thin film according toPreparation Example 1 shows higher crystallinity than that of organicthin film according to Comparative Preparation Example 1. Likewise,referring to FIGS. 4 and 5 , the organic thin film according toPreparation Example 2 shows higher crystallinity than that of organicthin film according to Comparative Preparation Example 2. Accordingly,the fused polycyclic aromatic compound having an asymmetric corestructure may show higher crystallinity than the fused polycyclicaromatic compound having a symmetric core structure.

Evaluation II

Thermal properties of the organic thin films according to PreparationExamples 1 and 2 are examined.

The thermal properties of the organic thin films are evaluated throughTA Instruments Discovery Differential Scanning calorimeter (DiscoveryDSC).

The results are shown in Table 1.

TABLE 1 Liquid Crystal Phase Transition Temperature (° C.) PreparationExample 1 140 Preparation Example 2 140

Referring to Table 1, the thin films according to Preparation Examples 1and 2 are present as a liquid crystal at a desired (and/or alternativelypredetermined) temperature region, and accordingly, a molecularalignment in the liquid crystal phase section may be expected to beimproved through a heat treatment.

Manufacture of Thin Film Transistor Example 1-1

First, a silicon wafer substrate coated with 3000 Å thick SiO₂ isexposed to 02 plasma and then, dipped in an octadecyl trichlorosilanesolution diluted in hexane to a concentration of 4 mM to change thesurface to be hydrophobic. Subsequently, the compound obtained inSynthesis Example 1 is vacuum-vapor deposited on the substrate to be 500Å thick at a substrate temperature of 70° C. to form an organicsemiconductor. Then, source and drain electrodes are formed on theorganic semiconductor by using a shadow mask and depositing Au to be1000 Å thick to manufacture a thin film transistor.

Example 1-2

A thin film transistor is manufactured according to the same method asExample 1-1, except for additionally annealing the organic semiconductoron a hot plate in a nitrogen glove box at 100° C. for 10 hours in thestep of forming the organic semiconductor.

Example 1-3

First, a silicon wafer substrate coated with 3000 Å thick SiO₂ isexposed to 02 plasma, dipped in a trimethoxy (2-phenylethyl)silane((3-PTS) solution diluted to be a concentration of 4 mM in toluene forone hour, and then has an extra solution on the surface removed, andexposed to ammonia vapor for greater than or equal to 10 hours to modifythe surface with β-PTS. Subsequently, the compound according toSynthesis Example 1 is dissolved to be a concentration of 0.4 wt % in ano-dichlorobenzene solvent, and a solution obtained therefrom is drippedon the substrate on a hot plate heated at 120° C. to form an organicsemiconductor in a gap cast method (for example, refer toAdv.Mater.2011, 23, p. 3681 to 3685). Then, source and drain electrodesare formed on the organic semiconductor by using a shadow mask anddepositing Au to be 1000 Å thick to manufacture a thin film transistor.

Example 1-4

A thin film transistor is manufactured according to the same method asExample 1-3, except for additionally annealing the organic semiconductoron a hot plate in a nitrogen glove box at 100° C. for 10 hours in thestep of forming the organic semiconductor.

Example 2-1

A thin film transistor is manufactured according to the same method asExample 1-1, except for using the compound according to SynthesisExample 2 instead of the compound according to Synthesis Example 1.

Example 2-2

A thin film transistor is manufactured according to the same method asExample 2-1, except for additionally annealing the organic semiconductoron a hot plate in a nitrogen glove box at 140° C. for 2 hours in thestep of forming the organic semiconductor.

Example 2-3

A thin film transistor is manufactured according to the same method asExample 1-3 except for using the compound according to Synthesis Example2 instead of the compound according to Synthesis Example 1 and a 0.2 wt% concentration solution instead of the 0.4 wt % concentration solution.

Comparative Example 1-1

A thin film transistor is manufactured according to the same method asExample 1-3 except for using the compound according to ComparativeSynthesis Example 1 instead of the compound according to SynthesisExample 1.

Comparative Example 1-2

A thin film transistor is manufactured according to the same method asExample 1-3, except for using the compound according to ComparativeSynthesis Example 1 instead of the compound according to SynthesisExample 1 and a 0.2 wt % concentration solution instead of the 0.4 wt %concentration solution.

Comparative Example 2-1

A thin film transistor is manufactured according to the same method asExample 1-1, except for using the compound according to ComparativeSynthesis Example 2 instead of the compound according to SynthesisExample 1.

Comparative Example 2-2

A thin film transistor is manufactured according to the same method asExample 1-3, except for using the compound according to ComparativeSynthesis Example 2 instead of the compound according to SynthesisExample 1 and a 0.2 wt % concentration solution instead of the 0.4 wt %concentration solution.

Evaluation III

Charge mobility of the thin film transistors according to Examples andComparative Examples is calculated.

The charge mobility of the thin film transistors is calculated byobtaining a graph having (I_(SD))^(1/2) and V_(G) as variables from asaturation region current equation and a slope in the graph.

${I_{SD} = {\frac{{WC}_{0}}{2L}{\mu( {V_{G} - V_{T}} )}^{2}}}{\sqrt{I_{SD}} = {\sqrt{\frac{{\mu C}_{0}W}{2L}}( {V_{G} - V_{T}} )}}{{slope} = \sqrt{\frac{{\mu C}_{0}W}{2L}}}{\mu_{PBT} = {({slope})^{2}\frac{2L}{C_{0}W}}}$

In the equations, I_(SD) is a source-drain current, μ or μ_(FET) ischarge mobility, C₀ is electrostatic capacitance of a gate insulatinglayer, W is a channel width, L is a channel length, V_(G) is a gatevoltage, and V_(T) is a threshold voltage.

A cut-off leakage current (I_(off)) is obtained as a minimum current inan off-state as a current flowing in an off-state. A current on-offratio (I_(on)/I_(off)) is obtained as a ratio of a maximum current in anon-state relative to a minimum current in the off-state.

The results are shown in Tables 2 to 5.

TABLE 2 Charge mobility (cm²/Vs) Current on-off ratio (I_(on)/I_(off))Example 1-1 1.3 × 10⁻¹ 9.8 × 10⁵ Example 1-2 3.7 × 10⁻¹ 3.1 × 10⁶Comparative 9.5 × 10⁻³ 3.0 × 10⁵ Example 1-1

TABLE 3 Charge mobility (cm²/Vs) Current on-off ratio (I_(on)/I_(off))Example 1-3 2.1 × 10⁻¹ 1.7 × 10⁴ Example 1-4 3.3 × 10⁻¹ 2.4 × 10⁵Comparative 4.0 × 10⁻³ 1.0 × 10³ Example 1-2

TABLE 4 Charge mobility (cm²/Vs) Current on-off ratio (I_(on)/I_(off))Example 2-1 1.6 × 10⁻¹ 2.7 × 10⁵ Example 2-2 3.3 × 10⁻¹ 5.6 × 10⁶Comparative 9.3 × 10⁻³ 3.3 × 10³ Example 2-1

TABLE 5 Charge mobility (cm²/Vs) Current on-off ratio (I_(on)/I_(off))Example 2-3 1.4 × 10⁻¹ 2.5 × 10⁴ Comparative 3.7 × 10⁻³ 3.8 × 10²Example 2-2

Referring to Tables 2 to 5, the thin film transistors according toExamples show improved charge mobility and current on-off ratioscompared with the thin film transistors according to ComparativeExamples. In addition, the thin film transistors according to Examples1-2, 1-4, and 2-2 show much improved charge mobility and current on-offratios through the additional annealing. Furthermore, the thin filmtransistors according to Examples 1-3, 1-4, and 2-3 have equivalentelectrical characteristics in a solution process to in a depositionprocess. Accordingly, a fused polycyclic aromatic compound having anasymmetric core structure shows improved electrical characteristics.

While some example embodiments have been described, one of ordinaryskill in the art would understand that inventive concepts are notlimited to the disclosed embodiments, but, on the contrary, may includevarious modifications and equivalent arrangements included within thespirit and scope of the appended claims.

1. A thin film transistor comprising a gate electrode, an organicsemiconductor overlapping with the gate electrode, and a sourceelectrode and a drain electrode electrically connected to the organicsemiconductor, the organic semiconductor including a compoundrepresented by Chemical Formula 1A or 1B,

wherein, in Chemical Formulae 1A and 1B, X¹ and X² are different fromeach other and are independently one of O, S, Se, and Te, provided thatone of X¹ and X² is Se or Te, R¹ to R⁴ are independently one ofhydrogen, a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C6 to C30 aryloxy group, asubstituted or unsubstituted C3 to C30 heteroaryl group, a halogen, acyano group, or a combination thereof, provided that R¹ and R² aredifferent from each other, and n₁ is an integer ranging from 2 to 4, andsubstituted refers to replacement of hydrogen of a group by asubstituent selected from a halogen atom, a hydroxy group, a nitrogroup, a cyano group, an amino group, an azido group, an amidino group,a hydrazino group, a hydrazono group, a carbonyl group, a carbamylgroup, a thiol group, an ester group, a carboxyl group, a sulfonic acidgroup, a phosphoric acid group, a C1 to C20 alkyl group, a C2 to C20alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C3to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxygroup, a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl group,a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 toC15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and acombination thereof.
 2. The thin film transistor of claim 1, wherein theother of X¹ and X² is S.
 3. The thin film transistor of claim 1, whereinone of R¹ and R² is hydrogen, the other of R¹ and R² is one of asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof, and substituted refers to replacement of hydrogenof a group by a substituent selected from a halogen atom, a hydroxygroup, a nitro group, a cyano group, an amino group, an azido group, anamidino group, a hydrazino group, a hydrazono group, a carbonyl group, acarbamyl group, a thiol group, an ester group, a carboxyl group, asulfonic acid group, a phosphoric acid group, a C1 to C20 alkyl group, aC2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 arylgroup, a C3 to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1to C30 alkoxy group, a C1 to C20 heteroalkyl group, a C3 to C20heteroarylalkyl group, a C3 to C30 cycloalkyl group, a C3 to C15cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 to C30heterocycloalkyl group, and a combination thereof.
 4. The thin filmtransistor of claim 1, wherein one of R¹ and R² is one of a substitutedor unsubstituted C1 to C30 linear alkyl group, a substituted orunsubstituted C2 to C30 linear alkenyl group, a substituted orunsubstituted C2 to C30 linear alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, or a combination thereof, theother of R¹ and R² is one of a substituted or unsubstituted C1 to C30branched alkyl group, a substituted or unsubstituted C2 to C30 branchedalkenyl group, a substituted or unsubstituted C2 to C30 branched alkynylgroup, or a combination thereof, and substituted refers to replacementof hydrogen of a group by a substituent selected from a halogen atom, ahydroxy group, a nitro group, a cyano group, an amino group, an azidogroup, an amidino group, a hydrazino group, a hydrazono group, acarbonyl group, a carbamyl group, a thiol group, an ester group, acarboxyl group, a sulfonic acid group, a phosphoric acid group, a C1 toC20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, aC6 to C30 aryl group, a C3 to C30 heteroaryl group, a C7 to C30arylalkyl group, a C1 to C30 alkoxy group, a C1 to C20 heteroalkylgroup, a C3 to C20 heteroarylalkyl group, a C3 to C30 cycloalkyl group,a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 toC30 heterocycloalkyl group, and a combination thereof.
 5. The thin filmtransistor of claim 1, wherein one of R¹ and R² is one of a substitutedor unsubstituted C1 to C30 alkyl group, a substituted or unsubstitutedC2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30alkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, ora combination thereof, and the other of R¹ and R² is one of asubstituted or unsubstituted C6 to C30 aryl group, a substituted orunsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C3to C30 heteroaryl group, or a combination thereof, and substitutedrefers to replacement of hydrogen of a group by a substituent selectedfrom a halogen atom, a hydroxy group, a nitro group, a cyano group, anamino group, an azido group, an amidino group, a hydrazino group, ahydrazono group, a carbonyl group, a carbamyl group, a thiol group, anester group, a carboxyl group, a sulfonic acid group, a phosphoric acidgroup, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20alkynyl group, a C6 to C30 aryl group, a C3 to C30 heteroaryl group, aC7 to C30 arylalkyl group, a C1 to C30 alkoxy group, a C1 to C20heteroalkyl group, a C3 to C20 heteroarylalkyl group, a C3 to C30cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 to C15cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and acombination thereof.
 6. The thin film transistor of claim 1, wherein oneof R¹ and R² is a group represented by one of Chemical Formulae 2A to2C:

wherein, in Chemical Formulae 2A to 2C, Z¹ to Z³ are independently N orCR^(a), one of Z¹ to Z³ is N, X³ is one of O, S, Se, Te, NR^(b), orCR^(c)R^(d), m₁ is an integer ranging from 0 to 5, m₂ is an integerranging from 0 to 3, R⁵, R⁶ and R^(a) to R^(d) are independently one ofhydrogen, a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C6 to C30 aryloxy group, asubstituted or unsubstituted C3 to C30 heteroaryl group, a halogen, acyano group, or a combination thereof, when m₁ is two or more, each R⁵is the same or different and two adjacent R⁵'s are independently presentor linked with each other to form a ring, and when m₂ is two or more,each R⁶ is the same or different and two adjacent R⁶'s are independentlypresent or linked with each other to form a ring, and substituted refersto replacement of hydrogen of a group by a substituent selected from ahalogen atom, a hydroxy group, a nitro group, a cyano group, an aminogroup, an azido group, an amidino group, a hydrazino group, a hydrazonogroup, a carbonyl group, a carbamyl group, a thiol group, an estergroup, a carboxyl group, a sulfonic acid group, a phosphoric acid group,a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynylgroup, a C6 to C30 aryl group, a C3 to C30 heteroaryl group, a C7 to C30arylalkyl group, a C1 to C30 alkoxy group, a C1 to C20 heteroalkylgroup, a C3 to C20 heteroarylalkyl group, a C3 to C30 cycloalkyl group,a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 toC30 heterocycloalkyl group, and a combination thereof.
 7. The thin filmtransistor of claim 1, wherein X¹ is O or S, X² is Se or Te, one of R¹and R² is hydrogen, and the other of R¹ and R² is one of a substitutedor unsubstituted C1 to C30 alkyl group, a substituted or unsubstitutedC2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30alkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, asubstituted or unsubstituted C6 to C30 aryl group, a substituted orunsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C3to C30 heteroaryl group, a halogen, a cyano group, or a combinationthereof, and substituted refers to replacement of hydrogen of a group bya substituent selected from a halogen atom, a hydroxy group, a nitrogroup, a cyano group, an amino group, an azido group, an amidino group,a hydrazino group, a hydrazono group, a carbonyl group, a carbamylgroup, a thiol group, an ester group, a carboxyl group, a sulfonic acidgroup, a phosphoric acid group, a C1 to C20 alkyl group, a C2 to C20alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C3to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxygroup, a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl group,a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 toC15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and acombination thereof.
 8. The thin film transistor of claim 1, wherein X¹is O or S, X² is Se or Te, one of R¹ and R² is one of a substituted orunsubstituted C1 to C30 linear alkyl group, a substituted orunsubstituted C2 to C30 linear alkenyl group, a substituted orunsubstituted C2 to C30 linear alkynyl group, a substituted orunsubstituted C1 to C30 alkoxy group, or a combination thereof, and theother of R¹ and R² is one of a substituted or unsubstituted C1 to C30branched alkyl group, a substituted or unsubstituted C2 to C30 branchedalkenyl group, a substituted or unsubstituted C2 to C30 branched alkynylgroup, or a combination thereof, and substituted refers to replacementof hydrogen of a group by a substituent selected from a halogen atom, ahydroxy group, a nitro group, a cyano group, an amino group, an azidogroup, an amidino group, a hydrazino group, a hydrazono group, acarbonyl group, a carbamyl group, a thiol group, an ester group, acarboxyl group, a sulfonic acid group, a phosphoric acid group, a C1 toC20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, aC6 to C30 aryl group, a C3 to C30 heteroaryl group, a C7 to C30arylalkyl group, a C1 to C30 alkoxy group, a C1 to C20 heteroalkylgroup, a C3 to C20 heteroarylalkyl group, a C3 to C30 cycloalkyl group,a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 toC30 heterocycloalkyl group, and a combination thereof.
 9. The thin filmtransistor of claim 1, wherein X¹ is O or S, X² is Se or Te, one of R¹and R² is one of a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C2 to C30 alkenyl group, a substituted orunsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1to C30 alkoxy group, or a combination thereof, and the other of R¹ andR² is one of a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, or a combination thereof, andsubstituted refers to replacement of hydrogen of a group by asubstituent selected from a halogen atom, a hydroxy group, a nitrogroup, a cyano group, an amino group, an azido group, an amidino group,a hydrazino group, a hydrazono group, a carbonyl group, a carbamylgroup, a thiol group, an ester group, a carboxyl group, a sulfonic acidgroup, a phosphoric acid group, a C1 to C20 alkyl group, a C2 to C20alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C3to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxygroup, a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl group,a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 toC15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and acombination thereof.
 10. The thin film transistor of claim 1, whereinthe compound is represented by a structure among structures in Group 1:

wherein, in Group 1, R¹ and R² are independently one of hydrogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof, provided that R¹ and R² are different from eachother, and substituted refers to replacement of hydrogen of a group by asubstituent selected from a halogen atom, a hydroxy group, a nitrogroup, a cyano group, an amino group, an azido group, an amidino group,a hydrazino group, a hydrazono group, a carbonyl group, a carbamylgroup, a thiol group, an ester group, a carboxyl group, a sulfonic acidgroup, a phosphoric acid group, a C1 to C20 alkyl group, a C2 to C20alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C3to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxygroup, a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl group,a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 toC15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and acombination thereof.
 11. The thin film transistor of claim 1, whereinthe compound is represented by a structure among structures in Group 2:

wherein, in Group 2, R^(1a) is hydrogen or a substituted orunsubstituted C1 to C30 alkyl group, Z¹ to Z³ are independently N orCR^(a), provided that one of Z¹ to Z³ is N, X³ is one of O, S, Se, Te,NR^(b), or CR^(c)R^(d), p and q are independently an integer of 1 to 30,and R^(p) and R^(a) to R^(d) are independently one of hydrogen, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxygroup, a substituted or unsubstituted C6 to C30 aryl group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or acombination thereof, and substituted refers to replacement of hydrogenof a group by a substituent selected from a halogen atom, a hydroxygroup, a nitro group, a cyano group, an amino group, an azido group, anamidino group, a hydrazino group, a hydrazono group, a carbonyl group, acarbamyl group, a thiol group, an ester group, a carboxyl group, asulfonic acid group, a phosphoric acid group, a C1 to C20 alkyl group, aC2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 arylgroup, a C3 to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1to C30 alkoxy group, a C1 to C20 heteroalkyl group, a C3 to C20heteroarylalkyl group, a C3 to C30 cycloalkyl group, a C3 to C15cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 to C30heterocycloalkyl group, and a combination thereof.
 12. An electronicdevice comprising the thin film transistor of claim 1.